Solve for $k$ : $k - 23 = 13$
Answer: Add $23$ to both sides: $ \begin{eqnarray} \\ k - 23 &=& 13 \\ \\ {+23} && {+23} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{-23 + k} &\hphantom{=}& \hphantom{13} \\ k &=& 13 {+ 23} \\ \end{eqnarray} $ Simplify. $ k = 36$